Propaganda and other forms of “junk news” on Twitter flowed more heavily in a dozen battleground states than in the nation overall in the days immediately before and after the 2016 presidential election, suggesting that a coordinated effort targeted the most pivotal voters, researchers from Oxford University reported Thursday.

The volumes of low-quality information on Twitter — much of it delivered by online “bots” and “trolls” working at the behest of unseen political actors — were strikingly heavy everywhere in the United States, said the researchers at Oxford’s Project on Computational Propaganda. They found that false, misleading and highly partisan reports were shared on Twitter at least as often as those from professional news organizations.

But in 12 battleground states, including New Hampshire, Virginia and Florida, the amount of what they called “junk news” exceeded that from professional news organizations, prompting researchers to conclude that those pushing disinformation approached the job with a geographic focus in hopes of having maximum impact on the outcome of the vote.